Scenario Answers

The answers provided in this section are not necessarily the only possible answers to the questions. The questions are designed to test your knowledge and to give practical exercise in certain key areas. This section is intended to test and exercise skills and concepts detailed in the body of this chapter.

If your answer is different, ask yourself whether it follows the tenets explained in the answers provided. Your answer is correct not if it matches the solution provided in the book, but rather if it has included the principles of design laid out in the chapter.

In this way, the testing provided in these scenarios is deeper: It examines not only your knowledge, but also your understanding and ability to apply that knowledge to problems.

If you do not get the correct answer, refer back to the text and review the subject tested. Be certain to also review your notes on the question to ensure that you understand the principles of the subject.

Scenario 16-1 Answers

1.Give reasons to support Humugos's desire to have multiple connections to the Internet.
Multiple connections to the Internet would not only provide redundancy, but could also be configured to load balance traffic into the Internet. If load balancing is not an option because the multiple connections are to different ISPs, traffic management could still be enforced by using each link for different purposes. Tuning the attributes and configuring prefix lists would do this very effectively.
2.Using Figure 16-3, issue the configuration commands that would allow Router B to select the path to network via Router G when connecting to the Internet. Use the local preference attribute to select the path.
Given the design of the network, the path to network has a longer AS_Path through Router G. Tuning the local preference to select this path means altering the selection that it would naturally have taken. The configuration commands are as follows:
Router B(config)# router bgp 100
network mask
neighbor remote-as 100
neighbor remote-as 250
bgp default local-preference 250

Remember that the higher the preference, the more likely the selection.